Iain Murray on rudder changes: It simply makes the boats safer

Gilles Martin-Raget / America's Cup

As a sailor, yacht designer, and race administrator, Iain Murray was a natural choice for the America's Cup teams when they selected a Regatta Director for the 2013 America’s Cup and CEO of America’s Cup Race Management.

As a sailor, Murray has won a record six consecutive 18ft Skiff World Championships, from 1977 to 1982. His success in the 18’ skiffs led to his selection as helmsman of his 1983 challenger Advance. Murray joined with the Kookaburra syndicate for Australia’s defense of the Cup in 1987 where they earned the right to defend the Cup. Murray also led the Spirit of Australia challenge for the 1992 Challenger Series. In 1995 Murray was a member of oneAustralia syndicate, which saw their IACC boat fracture and sink whilst racing against the winning New Zealand yacht. He has logged 18 Sydney-Hobart Races, including three overall victories and five line honors wins culminating in breaking their own race record in 2012.

From 1995-2001, Iain Murray was on the Australian Maritime Safety Authority, including serving as Deputy Chairman for three years from 1998.

Here, Iain Murray writes about his 37 safety recommendations, with a particular focus on the "rudder elevators":

Following the loss of Andrew Simpson when Artemis Racing capsized, I convened an expert safety review committee to consult with sailors, designers, engineers and shore team personnel to assess safety. After their review, I issued 37 safety recommendations to ensure our racing this summer will be as safe as possible.

Of the 37 recommendations, all have been strongly supported by the teams except for the one dealing with rudder elevators.

Currently, there is a lot of misinformation about what this recommendation is and what it means. There are two main factors to consider - the size of the rudder elevators and their angle of attack, plus a third point.

In simple terms rudder elevators are winglets on the rudder blade which act as control surfaces. The elevators are horizontal and control the pitch of the yacht. As with any rudder, a large surface area provides better control but comes with a drag cost.

My safety recommendations increase the span of the rudders to a minimum of 2.1 metres and stipulate a minimum size of the elevators at .32 square metres, attached to the bottom of the rudder in the most submerged position possible.

The aim is to minimise the chance of a pitch-pole (when the bow of the boat submerges and the stern rises out of the water). The AC72s need control at all times as they are travelling in excess of 40 knots and the hydrodynamic loads when turning the rudders /elevators at speed is substantial.

The current rule forces each competitor to fix the angle of the elevators each morning by 8:00 a.m., when the boat is measured. But different angles of attack on the elevators are necessary for different wind strengths. Under my safety recommendation, the teams can adjust the angle of attack on the elevators up until five minutes before the race start, allowing for more control in the conditions they are likely to encounter in that race. Under the current rule and under my proposal, the elevators can not be adjusted while racing.

After consultation with the teams over the past two weeks, I have been persuaded on a third point. The elevators can be symmetrical or asymmetrical. The penalty for offsetting the elevator (referred to as asymmetric) to one side of the rudder is that it introduces a bending moment into the 2.1 metre span of the rudder and as a result the rudders need to be stronger and heavier in construction.

I have yet to hear a convincing argument from any team that my recommendation will not enhance control and thus safety during racing. What I have heard is that this recommendation will make the boats easier to control and more stable.

This is a safety issue, pure and simple. Deeper, submerged rudders, with bigger elevators and control surfaces fixed at the most appropriate angle of attack for the conditions simply make the boats safer.